Lapping machine



June 20, 1939. s. M. SHAW LAPPING MACHINE FiledAug. 19, 1958 2 Sheets-Sheet l INVENTOR A T RNE New NN WMA E June 20, 1939. l5 M, SHAW 2,163,438

LAPPING MACHINE Filed Aug. 19, 195s 2 sheets-sheet 2 IN VENTOR UL-E MM Patented June 20, 1939 UNITED STATES PATENT OFFICE Application August 19,

6 Claims.

This invention relates to lapping machines and in particular to machines used for lapping gears and the like.

The main object of this invention is to provide a novel method and means for lapping gears and the like which improves the tooth form or true involute thereof during the lapping operation rather than destroy it.

Another object of the invention is to provide a lapping machine which improves the tooth form and decreases helix wobble and eccentricity of gears being lapped simultaneously with providing the required lapped finish by applying a pair of laps to a gear at th-e correct center disltance at all times whereby to avoid the usual practice of cramping the gear and laps together during lapping by decreasing the correct center distances therebetween.

Another object of the invention is to provide a lapping machine for lapping gears and the like having means'uor applying the proper lapping pressure between the laps and the gear being lapped without the use of complicated and expensive hydraulic or mechanical brakes on the spindles of the said machine.

Another object of the invention is to provide a lapping machine which is simple and inexpensive to manufacture, easy to operate and which will improve rather than destroy the tooth form of gears being lapped thereby.

Other objects of the invention will become apparent by reference to the following detailed description taken in connection with the accompanying drawings, in which:

Fig. 1 is a plan view of a lapping machine embodying the invention in which certain portions of the housing are broken away to illustrate the mechanism therein, the helix of the adjustable lap spindle being shown in a non-lapping position.

Fig. 2 is an enlarged sectional View of the pressure limit clutch type hand wheel preferably employed to limit the application of lapping pressure to work being lapped.

Fig. 3 is a cross sectional View taken on the line 3-3 of Fig. 2 through the clutch of the hand wheel pressure limit clutch assembly.

Fig. 4 is a sectional view taken on` the line 4 4 of Fig. 2 showing a preferred means for adjusting the clutch ring of the said hand wheel pressure clutch disclosed in Fig. 2.

Fig. 5 is a more or less diagrammatic fragmentary cross sectional View of the novel lapping machine taken on the line 5-5 of Fig. 1.

Fig. 6 is a diagrammatic view showing the rela- 1938, Serial No. 225,789

tive position of work to be lapped and the laps of the novel lapping machine when the helix of the adjustable lap spindle thereof is in a nonlapping position as shown in Fig. l.

Fig. 'l is an enlarged fragmentary view showing the helix of the adjustable lap spindle in a full lapping position.

Fig. 8 is a diagrammatic View showing the re1- ative position of work being lapped and the laps of the novel lapping machine when the helix of the adjustable lap spindle thereof is in a full lapping position as shown in Fig. 7.

Referring now to the drawings wherein like nu.- merals refer to like and corresponding parts throughout the several views, the illustrative embodiment of the novel lapping machine disclosed ther-ein comprises a base 20 upon which longitudinally disposed lap spindles 2| and 22 are mounted in lateral spaced relationship to each other by means of transversely movable carriages 23 adapted to be xed in transverse. ways 24. A central helical idler gear 25 is rotatably mounted on a vertically disposed carriage 26 slidabie in the vertical ways 21 for vertical adjustment with respect to the lap spindles 2| and 22 to admit of setting the said lap spindles 2| and 22 at 'the desired lateral spacing to accommodate various sizes of work to be lapped. Work W to be lapped is carried on a suitable arbor 28 mounted free to rotate between centers 29 and 3|) xed on carriages 299 and 300 respectively adapted to be secured in the desired position in the longitudinal ways 3| by means of machine bolts 32. Quick acting center clamps 33 and 34 of the center 30 admit of rapid positioning of the work carrying arbor 28 between the centers 29 and 30. The said centers 29 and 30 and the work W rotatable therebetween are centered normal to the vertical center of the helical idler gear 25. The lap spindles 2| and 22 are positioned equidistant on each side of the said helical idler gear 25 and the centers 29 and 3|] are preferably located in horizontal alignment with and centrally between. the horizontal center lines of the said lap spindles 2| and 22.

The spindle 2| is rotatably mounted in the spindle housing 3E on suitable thrust type ball bearings 36 and is preferably driven by an electric motor 31 having a pulley 38 on the rotor thereof which is connected by means of a pair of V-belts 39 to a pulley 40 keyed to the rearwardly extending end of the said spindle 2|. A helical gear 4| keyed on the spindle 2| is provided to rotate the idler gear 25, the said helical gear 4| and the idler gear 25 being in mesh at all times. The spindle 22 is rotatably mounted in a spindle housing 42 on suitable thrust type ball bearings 36 and is driven by the idler gear 25 which is in constant mesh with a wide faced helical gear 43 keyed on a sleeve 44 which is in turn splined on the rearward end of the said spindle 22. The said spindles 2| and 22 have suitable laps 2I0 and 220 respectively xed on the forward ends thereof for rotation thereby, the said spindles 2| and 22 and the laps 2||l and 220 carried thereby are located to mesh at the proper center distances with the work W.

The spindle 2| may be termed a fixed spindle and the spindle 22 may be termed an adjustable spindle inasmuch as the moving of the sleeve 44 carrying the wide faced helical gear 43 axially on the spindle 22 and parallel to the axis of rotation of the idler gear 25 in mesh with the said wide faced helical gear 43 advances the rotation of the lap 220 and the work W in mesh therewith with respect to the lap 2 0 also in mesh with the work W whereby to apply lapping pressure between the laps 2|6 and 220 and the work W in mesh therewith.

The sleeve 44 on which the wide faced helical gear 43 is keyed is provided with a suitable circumferential groove 45 into which a shift fork 46 is positioned, the said shift fork 46 being connected to the upset end of a shift rod 41 by means of a nut 48 threaded thereon. The shift rod 41 is slidably mounted through a suitable boss 49 on the spindle housing 42 and has one end thereof threaded through a pinion gear 50 rotatably mounted in a hollow gear box 5| which is preferably formed as a portion of the said spindle housing 42. A worm gear 52 disposed below the said pinion gear 50 and meshed therewith is suitably journaled in the gear box 5| and is preferably turned by a pressure limit clutch 53 mounted on the extending end shaft 520 of the said worm gear 52.

The turning of the hand wheel 54 of the pressure limit clutch 53 slides the Wide faced helical gear 43 across the face of the helical idler gear 25 and causes the said wide faced helical gear 43, the spindle 22 and the lap 220 carried thereby to advance a fraction of a turn with respect to the spindle 2i and the lap 2|0 carried thereby whereby to apply lapping pressure between the laps 216 and 226 and the work W in mesh therewith.

The shift rod 41 preferably has a travel limit disc 55 mounted on the end thereof which contacts a suitable stop 56 adjustable by a hand wheel 51 to accurately limit the travel of the wide faced helical gear 43 and the advance of the lap 226 whereby to prevent lapping the work W beyond a definite depth. The said stop 56 is adjusted from time to time to compensate for the wear of the laps 2|0 and 220.

Referring now particularly to Figs. 2, 3 and 4, the pressure limit clutch generally designated by the numeral 53 in the drawings comprises an inner clutch disc 58 keyed on the extending shaft 520 of the worm gear 52 by means of a suitable key 59 and an outer clutch disc 60 rotatably mounted on the said shaft 520 having a hand wheel 54 keyed thereon by a suitable key 540 to admit of turning the same. The said outer clutch disc 6l) and hand wheel 54 are prevented from sliding off the end of the said shaft 52D by means of a retainer plate 6| secured to the end of the said shaft 520 by a machine screw 62.

The said inner clutch disc 58 is preferably provided with a split clutch ring 63 located around the. annular clutch ring boss 580 of the said inner clutch disc 58 pinned to the said inner clutch disc 58 diametrically opposite the split therein by means of a suitable pin 64. The ends 65 of the said split clutch ring 63 are beveled radially and are urged apart and into contact with the clutch surface around the inner periphery of the annular boss 600 of the outer clutch disc 6D by means of a complementarily beveled wedge 66 having a round adjusting screw shank 660 swiveled thereto and threaded through the clutch disc diametrically opposite the clutch ring pin 64. The said split clutch ring 63 is normally sprung to the annular clutch ring boss 580 of the inner clutch disc 58 and runs free of the clutch surface of the outer clutch disc 6U. When the adjusting screw 660 of the wedge draws the said wedge between the beveled ends of the said split clutch ring 63 it is increased in outside diameter into frictional contact with the clutch surface of the outer disposed clutch disc 6|). A lock nut 61 xes the adjustment of the said split clutch ring 63 in the desired frictional contact with .the said outer clutch disc 60.

When the work W is placed between the centers 29 and 30 for lapping, the wide faced helical gear 43 is in the position shown in Fig. l and the laps ZID and 22B-are positioned with respect to the work W substantially as indicated diagrammatically in Fig. 6. The lapping machine is started running by starting the electric motor 31 and the gears and laps rotate as indicated by the arrows marked R in Figs. 5, 6 and 8. The said wide faced helical gear 43 is moved axially with respect to the idler gear 25 in mesh therewith to the position indicated in Fig. 6 which advances the rotation of the lap 220 and work W in the direction indicated by the arrows marked A in Figs. 6 and 8 to the lapping position shown in Fig. 8. The lapping pressure and depth of lap is preferably regulated as hereinbefore described. Lapping compound may be applied to the laps 2|0 and 220 and the work W through a suitable nozzle 68 under control of a pet cock 69, the said lapping compound being preferably in fluid form and pumped to the nozzle 68 by suitable pumping means from a reservoir in the bottom of the base 2U into which the said lapping compound drains from the work W and laps 2|0 and 220 through troughs 10, drain apertures 1| and the ways 3|.

Obviously, other means such as hydraulic means or electric magnetic means for moving the wide faced helical gear 43 axially with respect to the idler gear 25 and other means for regulating the pressure of and depth of lap may be employed, the applicant having broadly disclosed a very simple, inexpensive and positive lapping machine adapted to lap gears and the like accurately to commercial tolerances simultaneously with improving the form of gears being lapped thereby. Although the work W has been indicated as a spur gear, the lapping machine will readily accommodate itself to other types of gear lapping by merely changing the laps 2|0 and 220 thereof to conform to the particular type of work on which the machine may be used.

Although but a single embodiment of the invention has been disclosed and described herein, it is obvious that many changes may be made in the size, shape, arrangement and details of the various parts thereof without departing from the spirit of the invention and it is not intended to limit the scope of the invention other than by thev terms of the appended claims.

I claim:

1. In a gear lapping machine, a pair of laterally spaced parallel lap spindles adapted to rotate at equal speed in the same direction, a gear lap on each spindle rotatable therewith, means for mounting a gear to be lapped in mesh with said laps freely rotatable by said laps, means for advancing the rotation of one lap with respect to the other during the rotation ci the said laps whereby to apply lapping pressure between said laps and the said gear to be lapped, and means for limiting the said advance of the rotation of one lap with respect to the other whereby to fix the maximum depth to which the work may be lapped.

2. In a gear lapping machine, a pair of laterally spaced parallel lap spindles adapted to rotate at equal speed in the same direction, a gear lap on each spindle rotatable therewith, means for mounting a gear to be lapped in mesh with said laps freely rotatable by said laps, means for advancing the rotation of one lap with respect to the other during the rotation of the said laps whereby to apply lapping pressure between said laps and the said gear to be lapped, means for limiting the amount of lapping pressure applied, and means for limiting the said advance of the rotation of one lap with respect to the other whereby to fix the maximum depth to which the work may be lapped.

3. In a gear lapping machine, a pair of laterally spaced lapping spindles each having a lap thereon disposed in lateral alignment with respect to each other, means for rotatably supporting a work gear to be lapped in mesh with said laps, means for rotating one lapping spindle; a gear train causing one lapping spindle to rotate the other at equal speed and in the same direction composed of a helical gear keyed on one lapping spindle, a helical gear splined on the other lapping spindle and a helical idler gear meshed therebetween; and means for sliding the helical gear splined on one of the lapping spindles axially with respect to the said helical idler gear whereby to advance the rotation of one lap with respect to the other during the rotation of both laps and the work gear whereby to rotate the said laps in lapping pressure contact with said work gear.

4. In a gear lapping machine, a pair of laterally spaced lapping spindles each having a lap thereon disposed in lateral alignment with respect to each other, means for rotatably supporting a work gear to be lapped in mesh with said laps, means for rotating one lapping spindle; a gear train causing one lapping spindle to rotate the other at equal speed and in the same direction composed of a helical gear keyed on one lapping spindle, a helical gear splined on the other lapping spindle and a helical idler gear meshed therebetween; means for sliding the helical gear splined on one of the lapping spindles axially with respect to the said helical idler gear whereby to advance the rotation of one lap with respect to the other during the rotation of both laps and the work gear whereby to rotate the said laps in lapping pressure contact with said work gear, and means for limiting the amount of lapping pressure applied.

5. In a gear lapping machine, a pair oi laterally spaced lapping spindles each having a lap thereon disposed in lateral alignment with respect to each other, means for rotatably supporting a work gear to be lapped in mesh with said laps, means for rotating one lapping spindle; a gear train causing one lapping spindle to rotate the other at equal-speed and in the same direction composed of a helical gear keyed on one lapping spindle, a helical gear splined on the l other lapping spindle anda helical idler gear meshed therebetween; means for sliding the helical gear splined on one of the lapping spindles axially with respect to the said helical idler gear whereby to advance the rotation of one lap with respect to the other during the rotation of both laps and the work gear whereby to rotate the said laps in lapping pressure contact with said work gear, and means for limiting the said ad- Vance of the rotation oi one lap with respect to the other whereby to x the maximum depth to which the work may be lapped.

6. In a gear lapping machine, a pair of laterally spaced lapping spindles each having a lap thereon disposed in lateral alignment with respect to each other, means for rotatably supporting a work gear to be lapped in mesh with said laps, means for rotating one lapping spindle; a gear train causing one lapping spindle to rotate the other at equal speed and in the same direction composed of a helical gear keyed on one lapping spindle, a helical gear splined on the other lapping spindle and a helical idler gear meshed therebetween; means for sliding the helical gear splined on one of the lapping spindles axially with respect to the said helical idler gear whereby toadvance the rotation of one lap with respect to the other during the rotation of both laps and the work gear whereby to rotate the said laps in lapping pressure contact with said work gear, means for limiting the amount of lapping pressure applied, and means for limiting the said advance of the rotation of one lap with respect to the other whereby to fix the maximum depth to which the work may be lapped.

STANLEY M. SHAW. 

